<template>
  <div class="type-nav">
    <div class="container">
      <div @mouseleave='leaveShow' @mouseenter='enterShow'>
        <h2 class="all">全部商品分类</h2>
        <!-- 三级联动 -->
        <!-- 动画效果transition -->
        <transition name='sort'>
          <div class="sort" v-show='show'>
          <!-- 利用时间委派+编程式导航实现路由跳转与传参 -->
          <div class="all-sort-list2" @click='goSearch'>
            <div class="item" v-for='(c1, index) in categoryList' :key='c1.categoryId'>
              <h3 @mouseover="changeIndex(index)" :class='{cur:currentIndex == index}'>
                <a :data-categoryName='c1.categoryName' :data-category1Id='c1.categoryId'>{{c1.categoryName}}</a>
              </h3>
              <!-- 二三级分类 -->
              <div class="item-list clearfix" :style="{display: currentIndex == index? 'block': 'none'}">
                <div class="subitem" v-for='c2 in c1.categoryChild' :key='c2.categoryId'>
                  <dl class="fore">
                    <dt>
                      <a :data-categoryName='c2.categoryName' :data-category2Id='c2.categoryId'>{{c2.categoryName}}</a>
                    </dt>
                    <dd>
                      <em v-for='c3 in c2.categoryChild' :key='c3.categoryId'>
                        <a :data-categoryName='c3.categoryName' :data-category3Id='c3.categoryId'>{{c3.categoryName}}</a>
                      </em>
                    </dd>
                  </dl>
                </div>
              </div>
            </div>
          </div>
        </div>
        </transition>
      </div>
      <nav class="nav">
        <a href="###">服装城</a>
        <a href="###">美妆馆</a>
        <a href="###">尚品汇超市</a>
        <a href="###">全球购</a>
        <a href="###">闪购</a>
        <a href="###">团购</a>
        <a href="###">有趣</a>
        <a href="###">秒杀</a>
      </nav>
    </div>
  </div>
</template>

<script>
// 使用state 数据
import { mapState } from "vuex"
// 引入loadsh
import throttle from "loadsh/throttle"
export default {
  name: "TypeNav",
  data() {
    return {
      currentIndex: -1,
      show: true
    }
  },
  // 组件挂载完毕，向服务器发请求 存储于仓库中
  mounted() {
    // 通知vuex发请求，获取数据，存储到仓库,写到APP根组件里
    // 如果不是home组件，将typenav隐藏;再添加鼠标移入事件
    if (this.$route.path !== '/home') {
      this.show = false
    }
  },
  computed: {
    ...mapState({
      // 对象的写法 右侧是一个函数，使用计算属性的时候立即执行，注入一个参数state,其实即为大仓库中的数据
      categoryList: (state) => {
        return state.home.categoryList
      },
    }),
  },
  methods: {
    // 鼠标进入一级菜单变蓝色
    changeIndex: throttle(function (index) {
      this.currentIndex = index
    }, 100),
    leaveShow () {
      this.currentIndex = -1
      if (this.$route.path !== '/home') {
        this.show = false
      }
    },
    // 鼠标移入，search显示三级联动组件
    enterShow () {
      this.show = true
    },
    goSearch(event) {
      // 问题：如何确定点击的是a标签？怎么确定a标签是一级二级三级分类？
      // a 添加自定义属性data-categoryName
      // 事件对象event获取点击对象节点，节点有一个属性datasset,可以获取自定义属性和属性值
      let element = event.target
      let { categoryname, category1id, category2id, category3id } =
        element.dataset
      if (categoryname) {
        // 确定一二三级分类id，同理添加自定义属性
        // 整理路由跳转参数
        let location = { name: "search" }
        let query = { categoryName: categoryname }
        if (category1id) {
          query.category1Id = category1id
        } else if (category2id) {
          query.category2Id = category2id
        } else {
          query.category3Id = category3id
        }
        location.query = query
        if (this.$route.params) {
          location.params = this.$route.params
          this.$router.push(location)
        }
      }
    },
  },
}
</script>

<style lang="less" scoped>
.type-nav {
  border-bottom: 2px solid #e1251b;

  .container {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    position: relative;

    .all {
      width: 210px;
      height: 45px;
      background-color: #e1251b;
      line-height: 45px;
      text-align: center;
      color: #fff;
      font-size: 14px;
      font-weight: bold;
    }

    .nav {
      a {
        height: 45px;
        margin: 0 22px;
        line-height: 45px;
        font-size: 16px;
        color: #333;
      }
    }

    .sort {
      position: absolute;
      left: 0;
      top: 45px;
      width: 210px;
      height: 461px;
      position: absolute;
      background: #fafafa;
      z-index: 999;

      .all-sort-list2 {
        .item {
          h3 {
            line-height: 30px;
            font-size: 14px;
            font-weight: 400;
            overflow: hidden;
            padding: 0 20px;
            margin: 0;

            a {
              color: #333;
            }
          }

          .item-list {
            display: none;
            position: absolute;
            width: 734px;
            min-height: 460px;
            background: #f7f7f7;
            left: 210px;
            border: 1px solid #ddd;
            top: 0;
            z-index: 9999 !important;

            .subitem {
              float: left;
              width: 650px;
              padding: 0 4px 0 8px;

              dl {
                border-top: 1px solid #eee;
                padding: 6px 0;
                overflow: hidden;
                zoom: 1;

                &.fore {
                  border-top: 0;
                }

                dt {
                  float: left;
                  width: 54px;
                  line-height: 22px;
                  text-align: right;
                  padding: 3px 6px 0 0;
                  font-weight: 700;
                }

                dd {
                  float: left;
                  width: 415px;
                  padding: 3px 0 0;
                  overflow: hidden;

                  em {
                    float: left;
                    height: 14px;
                    line-height: 14px;
                    padding: 0 8px;
                    margin-top: 5px;
                    border-left: 1px solid #ccc;
                  }
                }
              }
            }
          }

          // &:hover {
          //   .item-list {
          //     display: block;
          //   }
          // }
        }
        .cur {
          background-color: skyblue;
        }
      }
    }
    .sort-enter {
      height: 0;
    }
    .sort-enter-to {
      height: 461px;
    }
    .sort-enter-active {
      transition: all .5s linear;
    }
    .sort-leave {
      height: 461px;
    }
    .sort-leave-to {
      height: 0;
    }
    .sort-leave-active {
      transition: all .5s linear;
    }
  }
}
</style>
